[MW3] Cheat reset

15 years later, I decided to play MW3 (2011) again after it went on sale on Xbox. Three days of pure nostalgia and fun… until I joined a random lobby and, for absolutely no reason, some loser completely reset the progress on my 15+ year-old account.

Is there any way to fix this? I just wanted to casually enjoy one of my favorite games… 😞